1. Field of the Invention
The present invention relates to a scanning apparatus, and more particularly to a vertical scanning-type scanning apparatus.
2. Description of the Prior Art
Optical scanning devices, such as a flat bed scanner, is well known in the art and produces machine-readable image data signals that are representative of a scanned object, such as a photograph or a page of printed text. In a typical scanner application, the image data signals produced by a scanner may be used by a personal computer to reproduce an image of the scanned object on a suitable display device, such as a CRT or a printer.
Referring to FIG. 1, which is a schematically cross-sectional view of a prior flat bed scanner 100. A document 102 is positioned with one side facing downward on a transparent platen 104. The downward facing side of the document 102 is then scanned so as to convert the visual images contained thereon into an electronic image data that is useable by data processing machines and the like. A scanning head 106 horizontally moves under the transparent platen 104 for a scanning action. The scanning head 106 comprises a linear light source 108, a mirror assembly 110, a lens 114 and a photodetector 116. A motor 112 is mechanically coupled to the scanning head 106 by gears, cables or the like, to move the scanning head 106 along the length of the transparent platen 104. The light reflected from the transparent platen 104 is redirected into the lens 114 by the mirror assembly 110 and thence into the photodetector 116.
The photodetector 116 is preferably a charge coupled device (CCD) assembly configured as a linear serial array of discrete detector cells. Each detector cell of the photodetector 116 defines a document picture element or a pixel. The output scan signal from the photodetector 116 is coupled through a flexible cable 120 to an electronic controller 122 for conversion to digital forms. The electronic controller 122 also introduces drive signals to the motor 112. The electronic controller 122 incorporates the data processing and handling elements for exchanging data and signals with a remote processor in communication with the output cable 126.
The prior flat bed scanner 100 is placed with the transparent platen 104 in parallel with the placing surface. The scanning head 106 is moved along the length of the transparent platen 104 by the motor 112 driven by the electronic controller 122 to capture image data. Hence, the prior flat bed scanner 100 not only needs a larger occupied space but also a motor for moving the scanning head and a power source for driving the motor is also required.
Accordingly, an improved scanning apparatus, which can solve the above drawbacks, is desired, so that the occupied space can be reduced and the power source can be decreased.
It is one objective of the present invention to provide a scanning apparatus utilizing gravity acceleration for scanning, in which starting power is applied on a scanning head by gravity acceleration to downwardly move the scanning head for scanning.
It is another objective of the present invention to provide a scanning apparatus utilizing gravity acceleration for scanning, in which a scanning speed of a scanning head is determined by the starting power applied to the scanning head, which is controlled by a predetermined angle rotated by the scanning head.
It is a further objective of the present invention to provide a scanning apparatus utilizing gravity acceleration for scanning, which is a kind of a vertically scanning-type scanning apparatus which can reduce the occupied space.
It is still a further objective of the present invention to provide a scanning apparatus utilizing gravity acceleration for scanning, in which the starting power is applied to a scanning head by gravity acceleration. Therefore, a motor for driving the scanning head can be omitted, and the manufacturing costs can be reduced.
In order to achieve the above objectives of this invention, the present invention provides a scanning apparatus utilizing gravity acceleration for scanning. The scanning apparatus comprises a U-shaped housing, a shaft bearing, a housing and a scanning head. The U-shaped housing includes a base plate and two sidewalls. The shaft bearing is disposed within the U-shaped housing with two ends thereof respectively and rotationally fastened to one of the two sidewalls. The housing includes a transparent top plate, a transparent bottom plate, a hook-shaped element and a guiding rail. The shaft bearing passes through the housing in parallel with the transparent top plate and the transparent bottom plate such that the housing is rotationally fastened in the U-shaped housing. Both the transparent top plate and the transparent bottom plate serves as a scanning platform. The hook-shaped element is disposed between the transparent top plate and the transparent bottom plate close to a top corner of the housing. The guiding rail is vertically disposed in the housing opposite to the hook-shaped element. The scanning head is disposed downwardly moveable in the housing. The scanning head comprises a transparent housing, light source, mirror assembly, lens assembly and a photodetector. The transparent housing is provided with an engageable piece and a guiding piece. The engageable piece is disposed on the top end of the transparent housing to be engaged with the hook-shaped element for fastening the scanning head when the scanning head is placed on the top end of the housing. The guiding piece is disposed in the transparent housing opposite to the engageable piece and in cooperation with the guiding rail to guide the scanning head to move downward for scanning. The light source, mirror assembly, lens assembly and the photodetector are disposed within the transparent housing in a predetermined arrangement so as to capture image data while scanning. When the scanning head is going to scan, the engagement between the engageable piece and the hook-shaped element is released and the starting power is applied by gravity acceleration. Thereby the scanning head is guided to move downward to scan via cooperation between the guiding piece and the guiding rail. By way of rotating the shaft bearing to generate a predetermined angle between the housing and the base plate of the U-shaped housing to change the starting power, thereby changing a scanning speed of the scanning head.